<?phpnamespace Common\Model;use Think\Model\ViewModel;class ProductCommentViewModel extends ViewModel{	public $viewFields = array(		'ProductComment'=>array('id','product_id','member_id','body','publish_time','status'),		'Product'=>array('title'=>'producttitle','_on'=>'Product.id=ProductComment.product_id'),		'Member'=>array('nickname','user','_on'=>'Member.id=ProductComment.member_id'),	);}